Monopolar fuel cell stack coupled together without use of top or bottom cover plates or tie rods

Abstract

A monopolar fuel cell stack comprises a plurality of sealed unit cells coupled together. Each unit cell comprises two outer cathodes adjacent to corresponding membrane electrode assemblies and a center anode plate. An inlet and outlet manifold are coupled to the anode plate and communicate with a channel therein. Fuel flows from the inlet manifold through the channel in contact with the anode plate and flows out through the outlet manifold. The inlet and outlet manifolds are arranged to couple to the inlet and outlet manifolds respectively of an adjacent one of the plurality of unit cells to permit fuel flow in common into all of the inlet manifolds of the plurality of the unit cells when coupled together in a stack and out of all of the outlet manifolds of the plurality of unit cells when coupled together in a stack.

Description

RELATED APPLICATIONS[0001]The present application is related to U.S. Provisional Patent Application Ser. No. 60 / 371,053, filed on Apr. 9, 2002, which is incorporated herein by reference and to which priority is claimed pursuant to 35 USC 119.GOVERNMENT INTERESTS[0002]The invention described herein was made in the performance of work under a NASA contract, and is subject to the provisions of Public Law 96-517 (35 U.S.C. §202) in which the Contractor has elected to retain title.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The invention relates to fuel cells, and in particular to monopolar fuel stacks.[0005]2. Description of the Prior Art[0006]Although there are five primary types of fuel cells, one of the most common types is the polymer electrolyte membrane (PEM) fuel cell. A PEM fuel cell consists of several membrane electrode assemblies (MEAs) within gas diffusion layers and bipolar plates. The purpose of a fuel cell is to produce an electrical current. The chemi...

AI Technical Summary

Benefits of technology

[0011]A novel stack design is disclosed below that overcomes the limitations of the conventional bipolar fuel stacks bipolar fuel stacks is proposed. This new stack design offers a two-to-three fold improvement in power densities, suitable for manufacturing, uses inexpensive plastic materials, and straightforward to troubleshoot and assemble. Such a stack design will substantially improve the commercialization of portable direct methanol fuel cell power sources.

Problems solved by technology

Such bipolar plates and end plates are usually machined or molded with flow field from graphite composite and the typical cost $50-$100 / sq. foot, and become a major part of the costs of the stack.

Also, once such as stack is assembled, trouble shooting will require the entire stack to be dismantled if any of the cells in the center of the stack has to be accessed.

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